1. Field of the Invention
The present invention relates to the field of wide-view imagery. More particularly, the invention relates to wide-view imagery captured from a moving platform.
2. Description of the Prior Art
A variety of photographic systems that create panoramic images and even full spherical images are commercially available. Some of these systems use a single lens or mirror, such as the 0-360 One-Click Panoramic Optic. One disadvantage of such systems is that a lens or mirror creates the circular image. As a result, little more than half of the typically rectangular sensor is actually used. Furthermore, the resolution is limited to that of a single sensor—typically about 6 mega-pixel for reasonably high-end cameras. Other systems, such as immersive camera systems, stitch together pairs of hemispherical images captured with 180-degree fisheye lenses, correcting for the inherent distortion of such lenses. Having to use a fisheye lense is a disadvantage, because such lenses are expensive and distort the image considerably near the edges. While the panoramic mirrors on the market are far less expensive than fisheye lenses, images taken with panoramic mirrors have similar distortion. Still other systems use a wide variety of geometric arrangements of camera elements to achieve extreme wide angle or spherical views. An example of this is the dodecahedron arrangement of camera elements disclosed by McCutchen in U.S. Pat. No. 5,023,725. As is the case with other prior art, this configuration does not use the full sensor. Also, if this configuration is used in a moving environment, expensive high-speed sensors are required.
Any arrangement of the cameras and lenses described above may be used in a moving environment for full video imaging, that is, for capturing images at a speed of at least 15 frames per second, provided that all pixels in the image are captured nearly simultaneously. Cameras produced by Point Grey Research of Vancouver, B.C. are examples of such full-video-capable cameras that are commercially available. The primary and common disadvantage of this camera, as well as the various prior art cameras and imaging systems mentioned above is cost. In order to take images from a moving platform, all of the systems listed above require relatively expensive high-speed sensors.
Finally, software programs are available that allow one to create panoramic images with conventional cameras by stitching individual images into panoramas or 360-degree images. This approach has disadvantages in that the programs are very difficult and time consuming to use.
What is needed, therefore, is an imaging system that is capable of capturing wide-view images from a moving platform, with little or no distortion. What is further needed is such an imaging system that is as low-cost as possible.